The
US military is doing "prudent planning" in case it needs to
move its anti-ISIS operations out of Incirlik Air Base in southern
Turkey following the country's failed coup, several US defense
officials told CNN Tuesday.

The
Turkish government cut off the power to the base after the coup
attempt took place Friday, leaving it without a commercial power
supply for four days and counting.

The
Pentagon has been able to fully operate the base through generator
power but said it would be difficult to continue indefinitely.

While
fuel supplies for the generators could be brought in, the key is
whether it becomes too expensive and cumbersome given the high pace
of air strikes the US wants to continue flying out of the base. US
aircraft regularly conducts missions in northern Syria, where it is
battling ISIS. And both drones and surveillance aircraft are used to
monitor the border with Syria and conduct other reconnaissance
missions.

The
Pentagon is all but openly pressuring the Turks to turn the power
back on at Incirlik.

If
they don't, "I think it's safe to say over time that it could
become a limiting factor," said Peter Cook Pentagon press
secretary, referring to US operations there. "The concern would
be if it were a protracted period of time, then we would potentially
have to make adjustments."

The
critical value of Incirlik is its location in southern Turkey, which
allows the US to conduct a high volume of missions because it doesn't
require the extensive refueling that is needed when aircraft come
from bases further away in the Persian Gulf.

Moving
the aircraft out of Turkey would mean relocating more than a dozen
manned and unmanned aircraft plus dozens of personnel to another
country, US defense officials said, but did not disclose where they
might go. Placing some equipment in Italy or Iraq could be options.

Defense
Secretary Ash Carter spoke to his Turkish counterpart by phone
Tuesday, offering support and discussing the importance of Incirlik
Air Base. US officials are indicating they are hopeful the Turks will
turn the power back on in the coming days. But no firm promises have
been made so officials said that planning continues.

The
fact such contingency planning is underway for dealing with a NATO
ally is perhaps the clearest signal to date that the US remains
uncertain how much it can rely on Turkish military cooperation in the
wake of the continuing aftermath of the failed coup by elements of
the Turkish military.

Defense
officials said the Pentagon wants to find out not just when the power
will be restored at Incirlik, but also get a better idea of the way
ahead for the military in Turkey and how it will operate in the wake
of the coup.

The
Turks still have not given a clear explanation about why they cut the
power to Incirlik.

State
Department spokesman Mark Toner told reporters Tuesday, however, that
while "I don't have a determination one way or the other"
on whether the power was deliberately being kept off, "I don't
believe so, no."

Asked
whether it was purely a power issue or now also a diplomatic one,
Toner replied, "My understanding is that it's a power issue."

Steven
Cook, an expert on Turkish politics with the Council on Foreign
Relations, suggested Tuesday that the power was cut in part "to
demonstrate Turks have some leverage over the US."

Already
the Turks announced their minister of defense and foreign minister
would not be attending an upcoming meeting in Washington on ISIS
operations long in the works.

The
US has conducted airstrikes from the Turkish air base since August
2015 after extensive negotiations for access to the base from the
Turkish government.

The
Turks and US share the runway, but US personnel operate generally
from one portion of the base. US officials are making it clear they
do not want to have to pack up.

Cook
of the Council on Foreign Relations indicated that Ankara could be
signaling that -- after a year of negotiations between the US and the
government -- "what the Turks gave, they can take way."

Given
all the US effort to be able to use the base for attacks on ISIS, he
doesn't believe the US military "is going to get out and go on
its own volition," as much as it is frustrated, because of the
difficulty and expense of conducting anti-ISIS missions out of UAE,
Qatar or an aircraft carrier.

He
added, "There will probably be some change but it will probably
come from the Turks."

US
defense officials said that so far they see no evidence the Turks are
using the power supply cutoff as leverage to try to get the US to
extradite Fetullah Gulen, a cleric who lives in exile in Pennsylvania
and whom the Turks claim was behind the coup. US defense officials
said that it a diplomatic and legal matter to be separately resolved.

White
House spokesman Josh Earnest acknowledged yesterday that the US has
received electronic documents relating to him from Turkey. The US
said it needed to have evidence of Gulen's participation in the coup
before moving ahead with extradition.

President
Barack Obama discussed Gulen with Turkish President Recep Tayyip
Erdogan in a call Tuesday, according to Ernest.

A
statement describing the conversation put out after the call by the
White House made no mention of Incirlik, however.

The
Pentagon's primary concern is for Turkey to re-establish a senior
officer corps that is a reliable partner that the US military can
interact with and count on.

Officials
refused to comment on whether any planning is underway to also move
the nuclear weapons stockpile at Incirlik, should the need arise